A protection circuit for preventing power tube from being turned on by mistake

Abstract

The invention belongs to the technical field of power supplies, and relates to a protection circuit for preventing a power tube from being turned on by mistake. The circuit of the present invention mainly includes a switch node detection module and a discharge module; the switch node detection module consists of a first PMOS transistor MP1, a second PMOS transistor MP2, a first NMOS transistor MN1, a second NMOS transistor MN2, and a third NMOS transistor MN3 , a fourth NMOS transistor MN4, a first resistor R1, and a second resistor R2; the discharge module is composed of a first voltage-resistant NMOS transistor MNS1, a second voltage-resistant NMOS transistor MNS2, and a third voltage-resistant NMOS transistor MNS3. The beneficial effect of the present invention is that, in the power tube drive circuit, when the main switch tube is turned on, the rising slope of the switch node voltage can be quickly detected and corresponding protection actions can be taken, and instantaneous rapid discharge can be performed to slow down the voltage rise of the switch node slope, and when the voltage rise of the switch node is suppressed, the protection mechanism will be exited in time.

Description

technical field [0001] The invention belongs to the technical field of power supplies, and relates to a protection circuit for preventing a power tube from being turned on by mistake. Background technique [0002] At present, in the field of switching power supplies in many electronic applications, the operating frequency is getting higher and higher. Although this will reduce the size of the chip, it will also increase the complexity of the circuit design and the required precision. [0003] When the operating frequency of the circuit is high, even if an appropriate dead time is set, when the main switch is turned on, a large dV / dt is generated at the switch node, so that the rectifier may also be turned on. This is because the gate-to-drain parasitic capacitance of the rectifier tube produces a coupled current that leads to punch-through, which will cause greater loss. Therefore, at a high operating frequency, there is a problem that the switching loss of the power MOS tu...

AI Technical Summary

Problems solved by technology

This is due to the coupling current generated by the gate-drain parasitic capacitance of the rectifier tube, resulting in punch-through, which will bring greater loss

Therefore, at high operating frequency, there is a problem that the switching loss of the power MOS tube replaces the conduction loss

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